package 二叉树;

public class LC_669修剪二叉搜索树 {
    public class TreeNode {
        int val;
        TreeNode left;
        TreeNode right;
        TreeNode() {}
        TreeNode(int val) { this.val = val; }
        TreeNode(int val, TreeNode left, TreeNode right) {
            this.val = val;
            this.left = left;
            this.right = right;
        }
    }
    public TreeNode trimBST(TreeNode root, int low, int high) {
        if(root==null)
            return null;
        if(root.val<low)
            return trimBST(root.right,low,high);
        if(root.val>high)
            return trimBST(root.left,low,high);
        root.left=trimBST(root.left,low,high);
        root.right=trimBST(root.right,low,high);
        return root;
    }
}
